Overload-preventing handles

ABSTRACT

A handle of the type adapted to prevent overloading of a mechanism with which it is operably associated, wherein a significant length of the handle is designed such that all points lengthwise thereof will simultaneously experience the same bending stress when a mechanism-operating load is applied to the handle, thereby resulting in a noticeably bending deformation of the length of handle before failure of the handle.

United States Patent llarold V. Hawkins;

Ralph A. Dick, both of Williamsville, N.Y. 888,555 Dec. 29. i969 Aug.10, 1971 Columbus M'cKinnon Corporation Tonawanda, N.Y.

inventors Appl. No. Filed Patented Assignee OVERLOAD-PREVENTING HANDLES8 Claims, 6 Drawing Figs.

References Cited UNITED STATES PATENTS 1.243.614 l0/l9l7 Levalley 74/5232.243.361 5/l94l Stahl 254/167 Primary Examiner--William F. ODeaAssistant Examiner-F. D. Shoemaker Attorney-Bean & Bean ABSTRACT: Ahandle of the type adapted to prevent overloading of a mechanism withwhich it is operably associated, wherein a significant length of thehandle is designed such that all points lengthwise thereof willsimultaneously experience the same bending stress when amechanism-operating load is applied to the handle, thereby resulting ina noticeably bending deformation of the length of handle before failureof the handle.

Patented Aug. 10, 1971 2 Sheets-Sheet 2 I:II I EEZ 5:: 52:55::2:

ATTORNEYS OVERLOAD-PREVENTING HANDLES BACKGROUND OF THE INVENTION.

It is common practice to provide handles, which are designed to failunder a given applied loading below that which would result in damage toa mechanism with which they are operably associated.

Prior handle constructions of this type include tubular handies whosewalls are made sufficiently thin to fail by bending under apredetermined loading condition. One drawback of However, in allprevious overload-preventing handle con-' structions of which I amaware, bending is ofttimes accompanied by fracture or breaking of thehandle due to the fact that an operator does not notice the initiationof bending until it is too late to relieve the overloading condition.Moreover, even in cases where a handle formed in accordance with priorpractice does not completely fail, it is ofttimes too weak to permit anyfurther operation thereof. This is a particularly serious drawback insituations where operation of the deformed handle is required to releaseor return a mechanism. such as a ratchet puller, to a nonoverloadcondition.

SUMMARY OF THE INVENTION I The present invention generally relates tohandles'adapted' to prevent overloading of a mechanism which they serveto operate by undergoing bending deformation when a predetermined loadis applied to the handles by an operator.

More particularly, the present invention is directed towards a handlewherein an elongated portion of the handle intermediate the mounting andoperating ends thereof is designed such that all points in a directionlengthwise thereof simultaneously experience the same bending stresswhen a mechanism operating load is applied. As a result, when apredetermined operatingload is applied to the handle, the intermediateportion of the handle bends in a uniform manner In that bendingsimultaneously occurs over a significant length of the handle, thecumulative bending deformation of the handle is pronounced at theinitiation of the overload condition, so as to quickly and dramaticallybring to the attention of an operator the fact that an excessive loadhas been applied. This DRAWINGS FIG. 4 is an end view of the handle withreference being made to line 4-4 in FIG. 1;

FIG. 5 is a sectional view taken generally along the line 5-5 in FIG. l;and

FIG. 6 is a sectional view taken generally along the line 6-6 in FIG. 1.

DETAILED DESCRIPTION The handle of the present invention, which isgenerally? designated as l in the drawings, is preferably in the form ofan integrally metal casting having an end portion 2 for mounting thehandle on a mechanism to be operated, such as a ratchet puller 3; anoperating end portion 4 to which a mechanism operating load is to beapplied by an operator; and an intermediate or connecting portion 5.

Puller 3 is shown in FIG. 1 for purposes of reference only asincluding aframe 6, which is provided with a hook 7 for suspending the frame from asuitable support 8. Handle 1 is mounted for vertical swinging movementrelative to frame 6' by means ofa shaft 9 freely received withinmounting end portion aperture I0. Shaft additionally serves to rotatablysupport a lift wheel, not shown, which operably engages a lift' chain 12having a 'load-liftinghook l4; and a ratchet wheel 15,

' which is affixed for rotation with the lift wheel.

permits the operator to remove the predetermined operating load whilethe handle, although significantly deformed, retains sufficient strengthto permit its operation for the purpose of. releasing or returning themechanism with which it is associated to a nonoverloaded condition.

Uniform bending stress is produced in the intermediate portion of thehandle by progressively decreasing the section modulus thereof in adirection towards the operating portion of the handle. In accordancewith the preferred embodiment of the present invention, the intermediateportion of the hairdle is of l-shaped cross-sectional configuration andthe section modulus decreased by varying the height of a web connectinga pair of spaced flanges.

In a preferred construction the handle is in the form of a A suitableratchet-wheel-operating device, as for instance of the type shown anddescribed in U.S. Pat. No. 2,633,328, is employed to operably.interconnect handle I to ratchet wheel 15 for the purpose of controllingoppositely directed rotations thereof, which'result in either raising orlowering of load-lifting hook 14. For purposes of reference, theratchet-wheeloperating device is shown in FIG. 1 as including in part aratchet-wheel-actuating pawl 17 and a reversing lever 19, which arecarried by handle I, and a ratchet-wheel-locking pawl 20 and alocking-pawl-biasing spring 22, which are carried by frame 6. When it isdesired to raise load-lifting hook 14, an operator places lever 19 inits phantom line position shown in FIG. 1, and after gripping operatingend portion 4 applies a force or load F to swing handle 1 downwardly ina direction indicated by arrow 24. During such movement, ratchet wheel15 is rotated by actuating pawl 17 and locking pawl lllmerelyserves toretain the ratchet wheel in the rotatable position into which it isdriven by the actuating pawl.

When it isdesired to lower lifting hook 14, an operator places lever 19in its full line position shown in FIG. 1 and momentarily' pulls down onhandle I for the purpose of rotating' the puller.

As is conventional, handle intermediate portion 5 is designed such thatit is weaker than end portions 2 and 4 in order that it'wil-lrbeoverstressed first when a predetermined operating load is applied-tooperating end portion 4 above whichpuller 3 wouid be subjected to anoverloaded condition.

Thus, failure of intermediate portion 5 by bending will protectpullerlfrom beingoverloaded and once subjected to bending failure itwill be replaced by a new handle.

. It is a particular feature of the present invention that intermediateportion is configured such that bending stress produced therein, as aresult of a mechanism-operating force or load F applied to. endportion'4, is substantially constant. along'a significant length of theintermediate portion. as'for instance the length L between heavy dashedlines 26a, 261),

would result in complete failure of the handle or weakeningthereof tosuch an extent that it cannot be operatedtolower,

or release an overload handled by the puller.

Bending stress at any given point along length: L, asfor in.-

stance point P shown in FIG. 2, may be defined as being equal to M/Z,wherein M is a Moment which may be defined asload F multiplied by theMoment arm or Distance X- through which the load acts, and Z is thesection modulus of .the handle at point P. Thus, it will be apparentthat for any given load F, the section modulus Z must be progressivelydecreased along length L towards operating end portion 4 in order foruniform bending stress to be maintained at each point along length L.

By referring to FIGS. 1-3 and 6, it will be seen that in accordance withthe preferred embodiment of the present invention, intermediate portion5 is formed with a generally I- shaped cross-sectional configuration anddefined byan upper flange 28, a lower flange 29 and an intermediate orconnecting web 30. When employing this construction, the section modulusis preferably varied along length L by progressively decreasing theheight of web 30 in a direction towards operating end portion 4.

Another feature of the present invention is to form operating "endportion 4 with a generally Cshaped crosssectional configuration, whichas best shown in FIGS. 2, 4 and 5 is defined by an upper flange 32, alower flange 33and an intermediate or connecting web 34. To bothfacilitate the casting of handle I and produce a relatively strong,light weight structure, flanges 32, 33 and web 34 are connected to orformed as continuations of flanges 28, 29 and web 30, respectively;

Flanges 32, 33 and web 34 cooperate to provide an enlarged handle grip,which may be conveniently grasped by an opera? tor for the purpose ofapplying an operating load.

Formed integrally with opposite ends of flanges 32, 33 and web 34 aretransversely extending enlargements in the form of a bead 36 and endflange 38, which bound the handle grip and cooperate to prevent slippageof an operators hand therefrom.

Preferably, end flange 38 is arranged and dimensioned so as to preventthe placing of an additional lever arm, such as length of iron pipe,either about or between flanges 32, 33 for the purpose of increasing themoment which may be applied to puller 3. Otherwise, the possibilitywould cxist'tliat the length of pipe would be slid onto handle Isufficiently far so as to'cover intermediate portion 5 with the resultthat the puller could be damaged byoverloading thereof even thoughprovided with a handle according to the present invention.

While only the preferred embodiment of the handle of the presentinvention has been described in detail, it will be understood thatalternative constructions may be adopted without departing from thepractice of the invention. l-n this respect, the handle may be formed bymeans other than casting and the parts thereof have any desiredcross-sectional con-- figuration. Further, handles formed in accordancewith the present invention may be employed to operate diversemechanisms.

-tion.

-We claim:

l'. A .handle for preventing overloading of mechanism 0 erated by thehandle by undergoing bending deformation w en a predeterminedmechanism-operating load is applied thereto, said handle comprising: v

an end portion for mounting said handle on said mechanism; Atin-operating end portion to which"mechanism-operating loads are to beapplied; and p an intermediate portion connecting said end portions,said intermediate portion being elongated 3 in a direction lengthwise ofsaid handle and being characterized by configuration wherein sectionmodulus progressively decreases in a direction towards said operatingend portion such that bending stress produced in said intermediateportion as a result of a mechanism operating load applied to-saidoperating end portion is substantially constant at all points lengthwisethereof, said bending stress in said intermediate portion for alloperating loads being greater than in said end portions, whereby whensaid predetermined operating load is applied to said operating 7 endportion bending deformation of said handle occurs only in saidintermediate portion and bending deformation of said intermediateportion occurs substantially simultaneously at all points lengthwisethereof.

2. A handle according to claim 1, wherein said handle portions are ofintegrally formed construction.

3. A handle according to claim 1, wherein said intermediate portion isof l-shaped cross-sectional configuration defined by a pair ofspacedflange portions and a connecting web portion.

4. A handle according to claim 3, wherein said section modulus isdecreased by decreasing the height of said connecting web portion in adirection towards said operating end portion.

5. A handle according to claim 3, wherein at least said operating endand intermediate portions are of integrally formed construction, saidoperating end portion is of C- shaped configuration defined by a pair ofspaced flange portions and a connecting web portion, and said flange andweb portions of said operating end portion being formed continuous withsaid flange and web portions of said intermediate an 6. A handleaccording to claim 5, wherein said operating end portion is enlargedadjacent opposite ends thereof in a direction transversely of saidhandle.

7. A handle according to claim 3, wherein said operating endportion isof C-shaped cross-sectional configuration definedby a pair of spacedflange portions and a connecting web portion, said flange and connectingweb portions of said operating end portion being connected adjacent oneend thereof to said flange and web portions of said intermediate portionand being connectedradjacent another end thereof to a flange extendingoutwardly thereof in a direction transversely of said handle.

8. A handle according to claim I, wherein said handle portions are inthe form of an integral metal casting;

said intermediate portion is of l-shaped cross-sectional configurationhaving upper and lower flange portions and a connecting web portion.said operating end portion is of C-shaped cross-sectional configurationhaving upper and lower flange portions and a connecting web portion,said flange and web portions of said operating end portion being joinedadjacent one end thereof with said flange and web portions of saidintermediate portion,

said flange and web portions of said operating end portion beingprovidedadjacent said one end thereof and adjacent another end thereof withflange means extending die.

1. A handle for preventing overloading of mechanism operated by thehandle by undergoing bending deformation when a predeterminedmechanism-operating load is applied thereto, said handle comprising: anend portion for mounting said handle on said mechanism; an operating endportion to which mechanism-operating loads are to be applied; and anintermediate portion connecting said end portions, said intermediateportion being elongated in a direction lengthwise of said handle andbeing characterized by a configuration wherein section modulusprogressively decreases in a direction towards said operating endportion such that bending stress produced in said intermediate portionas a result of a mechanism operating load applied to said operating endportion is substantially constant at all points lengthwise thereof, saidbending stress in said intermediate portion for all operating loadsbeing greater than in said end portions, whereby when said predeterminedoperating load is applied to said operating end portion bendingdeformation of said handle occurs only in said intermediate portion andbending deformation of said intermediate portion occurs substantiallysimultaneously at all points lengthwise thereof.
 2. A handle accordingto claim 1, wherein said handle portions are of integrally formedconstruction.
 3. A handle according to claim 1, wherein saidintermediate portion is of I-shaped cross-sectional configurationdefined by a pair of spaced flange portions and a connecting webportion.
 4. A handle according to claim 3, wherein said section modulusis decreased by decreasing the height of said connecting web portion ina direction towards said operating end portion.
 5. A handle according toclaim 3, wherein at least said operating end and intermediate portionsare of integrally formed construction, said operating end portion is ofC-shaped configuration defined by a pair of spaced flange portions and aconnecting web portion, and said flange and web portions of saidoperating end portion being formed continuous with said flange and webportions of said intermediate portion.
 6. A handle according to claim 5,wherein said operating end portion is enlarged adjacent opposite endsthereof in a direction transversely of said handle.
 7. A handleaccording to claim 3, wherein said operating end portion is of C-shapedcross-sectional configuration defined by a pair of spaced flangeportions and a connecting web portion, said flange and connecting webportions of said operating end portion being connected adjacent one endthereof to said flange and web portions of said intermediate portion andbeing connected adjacent another end thereof to a flange extendingoutwardly thereof in a direction transversely of said handle.
 8. Ahandle according to claim 1, wherein said handle portions are in theform of an integral metal casting; said intermediate portion is ofI-shaped cross-sectional configuration having upper and lower flangeportions and a connecting web portion, said operating end portion is ofC-shaped cross-sectional configuration having upper and lower flangeportions and a connecTing web portion, said flange and web portions ofsaid operating end portion being joined adjacent one end thereof withsaid flange and web portions of said intermediate portion, said flangeand web portions of said operating end portion being provided adjacentsaid one end thereof and adjacent another end thereof with flange meansextending outwardly thereof in a direction transversely of said handle.